Generally, a conventional method used in facial bone contouring surgery employs a bone-cutting saw for cutting bone at a desired site. Since a large quantity of bone is cut using such a saw at once, the accuracy in bone cutting is difficult to achieve.
In order to accurately set a cutting angle, easily eliminate cut bone fragments from the bone and easily deliver the rasp to the desired cutting site, the above conventional method essentially requires that a visual field of the surgeon be secured, thus a large-sized incision for securing the visual field being needed. Accordingly, the conventional method has several problems such as severe swelling and excessive bleeding of the cutting site, delayed healing, cutting of vessels, nerve damage, etc.
Further, the saw for cutting bone may cause severe injuries to peripheral soft tissues around the incision during the movement.
Thus, there is required a more stable bone cutting method using a rasp. However, since there is not yet developed any device to meet this requirement, it is difficult to stably perform surgery using the rasp.
Compared with other surgeries, the facial bone contouring surgery must continuously grind down a large amount of bone in a short period of time, exhaust muscles and periosteum together with the ground bone fragments, and carry out the whole process thereof for a short time so as to minimize the bleeding and swelling of the incision. Further, since the facial bone contouring surgery requires a step of generally reducing the thickness of bone, an effective cutting plane contacting the bone must be a large area. Since bone fragments are accumulated, aggregated and compressed between blades of the conventional rasp during the operation, continuous cutting using the rasp is impossible. Thus, since blades of electric-powered or pneumatic rasps must be cleaned off every several seconds, it is impossible to grind a large amount of bone using these rasps in the facial bone contouring surgery. Further, the stacking of the bone fragments on the blades is made more severe by heat generated from the cutting plane of the electric-powered or pneumatic rasps. On the other hand, hand-powered rasps do not generate heat but have a low operational speed, thus being impractical to use.
The conventional electric-powered or pneumatic devices cannot be inserted under the skin via a small incision so as to continuously grind a large amount of bone. These conventional devices have limitedly been used to remove a small amount of bone. However, these devices have a structure which cannot be used in facial bone contouring surgery. Further, in order to use a device in the facial bone contouring surgery, the device must have a constitution such that muscle fragments and periosteum with comparatively large sizes together with the ground bone fragments are exhausted from the body to the outside. Simultaneously, in order to allow the device to be inserted beneath the skin via a small incision, the device must have a cutting plane with large length relative to the outer diameter of the device. However, the conventional devices do not meet these requirements, thus not being used in facial bone contouring surgery.
A bone cutting rasp used in facial bone contouring surgery is used at a position and angle differing from those of the conventional bone cutting device. That is, a small-sized osteophyte or cartilage can be removed by a rasp with a small interface with the osteophyte or cartilage, while a broad, flat and solid surface of a facial bone is ground to have a desired shape by a rasp with a broad interface with the surface of the facial bone. The cutting plane of the rasp required to grind the facial bone (such as mandibular angle and zygomatic bone contouring) is maximally 40 mm. In order to uniformly grind the facial bone, the rasp must have a length of at least 30 mm.
U.S. Pat. No. 6,368,324 discloses a surgical handpiece adaptor assembly comprising an adaptor with a mechanism for converting rotary motion of a powered surgical handpiece into reciprocating motion, and a cutting member, such as a rasp, provided with a tissue cutting surface and a suction passage with an inlet opening along the tissue cutting surface. The cutting member coupled with a distal end of a front drive shaft of the adaptor is inserted beneath the skin at an operative site for cutting and removing anatomical debris such as the nasal bone from the operative site at which the rasp is used.
The cutting member of this patent is delivered to the operative site via a minimum incision, cuts a desired bone in the operative site, and exhausts the cut fragments of the bone via the inlet, thus solving the above-described problems of the conventional bone-cutting saws.
However, this assembly cannot supply a saline solution to the cutting surface, thus not eliminating heat generated on the cutting surface when a large quantity of bone such as zygomatic bone, maxilla or mandible is continuously removed. Further, the inlet has a structure such that the continuous cutting of bone cannot be performed and bone debris aggregated and compressed between blades of the rasp cannot be exhausted to the outside, thus requiring frequent cleaning. Accordingly, this assembly can be used in surgical facial procedures such as rhinoplasty and supraorbital procedures, but cannot be effectively used in the skin overlying the area of the supraorbital bone that is to be reshaped or contoured.
That is, in the facial bone contouring surgery such as angle ostectomy or maloplasty, a large quantity of bone must be cut or ground off. Here, heat is generated due to friction between the rasp and the bone, thus causing damages such as burning of soft tissues or deformation of tissues. Further, the cut fragments of bone are aggregated during cutting and accumulated between blades of the rasp, thus not being exhausted to the outside and remarkably reducing the cutting efficiency of the assembly.
The bone cutting is also performed so as to collect bone fragments for bone tissue culture. Since the collected bone fragments are damaged by the heat generated due to friction between the rasp and the bone, it is difficult to use the damaged bone fragments in bone tissue culture. Further, during the driving of the cutting member, the cutting member irritates and damages peripheral soft tissues around the operative site.
Further, the assembly does not have a double tube structure, thus not protecting peripheral regions around the operative site during the insertion and operation of the rasp, and causing inconvenience to a surgeon in case that the rasp is inserted into the operative site via a small and deep incision. Since the friction generated between the cutting plane of the rasp operated at a high speed and the bone damages peripheral tissues, this assembly is not suitable for use in facial bone contouring surgery.
U.S. Pat. No. 5,540,693 discloses cutting means provided with a motor-driven cutter and a double conduit. However, since heat generated on this cutting means cannot be eliminated and bone crash is accumulated between blades of the cutter, the cutting means is not suitable for use in removal of a large quantity of bone or for facial bone contouring surgery. A shaft of the cutting means is used as a suction tube. Accordingly, the cutting means of this patent provides a broad passage via even a small incision, and has a double tube structure provided with a protection tube, thus protecting peripheral tissues around an operative site. However, an inlet does not pass through the cutting plane, thus generating many bone fragments and causing a difficulty in sucking large-sized tissue fragments.
U.S. Pat. Nos. 5,643,304 and 5,403,276 disclose motor-driven surgical rasps for use in cartilage and/or bone removal, each of which comprises a protective double cannula structure for feeding saline solution and sucking removed tissues via slits formed between blades of the rasp. This rasp prevents the aggregation of bone fragments and the damage of peripheral tissues due to frictional heat, but has several disadvantages. That is, the slits between the blades of the rasp are easily clogged with the cut bone fragments. Further, since the shaft of a cutter serves as a saline solution feeding pipe and an external pipe serves as a suction pipe, the external pipe must have an enlarged diameter so as to suck large-sized bone fragments.
Moreover, in this structure, the bone fragments obtained by grinding move toward a cutting plane along the inner wall of the rasp. Thus, this structure must have through-holes formed between the blades of the rasp so as to prevent the clogging of the bone fragments. Although the saline solution is sprayed via the through-holes, since the spraying pressure of the saline solution is smaller than the suction pressure of the bone fragments, the through-holes are easily clogged with the bone fragments. Therefore, in case that the through-holes of a part of the plural blades of the rasp are clogged with the bone fragments and do not spray saline solution, the number of usable blades of the rasp is reduced. Accordingly, this structure is usefully employed in a small cutter for removing a small quantity of bone, which includes only two or three blades and saline solution feeding slits, but is not employed in a large-sized long cutter for simultaneously removing a large quantity of bone, periosteum and muscles at a high speed, such as facial bone contouring surgery, which includes a plurality of blades.
In order to perform continuous cutting, comparatively large-sized holes must be formed through the cutting planes between the blades so that the suction pipe is formed according to the moving direction of the bone fragments and the direction of suction pressure. However, the above structure does not meet this requirement. Further, with the above structure, it is impossible to form the maximum cutting plane via the minimum outer diameter of the cutter. For this reason, the rasp having this structure is not used in facial bone contouring surgery.
This rasp is used in endoscopic operations such as operations on geniculate cartilage or spine. That is, the rasp having this structure is used to remove only a small quantity of tissues, which contact the exposed tip of the blade or are sucked by the external pipe, and a small-sized osteophyte. Accordingly, with the rasp, it is impossible to actively cut a broad, flat and solid plane of bone such as zygoma, maxilla or mandible.
U.S. Pat. No. 4,766,701 discloses a hand-powered vacuum rasp comprising a plurality of downward-facing openings formed through an abrading work surface. This hand-powered rasp sucks only air via the openings, but does not feed saline solution for removing generated heat and remove bone fragments at a high speed. Further, the rasp does not have a double cannula structure, and the size of the openings is not sufficient to suck the cut bone fragments together with air. Moreover, it is difficult to manufacture a cutter of the rasp being suitable for use in facial bone contouring surgery. The hand-powered vacuum rasp has a suction structure in a shaft of the cutter and suction openings formed through the cutting plane. However, the hand-powered vacuum rasp having this suction structure cannot be used in facial bone contouring surgery.
In addition, U.S. Pat. Nos. 5,269,798, 5,286,253, and 5,364,395 disclose various instruments for use in cartilage and/or bone removal, in which saline solution feeding and tissue cutting are simultaneously performed. However, these instruments perform the tissue cutting using a rotary blade, thus causing exposed portions of nerves and vessels in facial bone contouring surgery to be dangerously rolled into the blade. Further, these instruments remove only portions sucked into protrusions or an external pipe, thus not being used in reduction of a broad area such as facial bone contouring surgery.